You need to know the total wattage of the lights, then you can convert that to amperage and then you can pick the rating of the components to use to wire the circuit for the lights.
BUT... Based on 150 watts each or 300 watts total circuit rating here is a few numbers.
300w / 12 volts = 25 amps total draw.
A 30 amp relay would work fine but a 40 amp relay with a 30 amp fuse on the power load or to pin 30.
10 gauge wire if both lights are on the same wire or two 12 gauge wires.
The relay actuation circuit can be run from the main circuit panel, a 1 or 2 amp fuse to a switch, then to pin 85 on the relay.
If the lights are 100 watts each then total draw is 17 amps and the 30 amp relay with a 20 amp fuse minimum will work on the power pin.
Anything else you want to know ?